ShaftCPM

ShaftCPM is a spectrum analyzer that measures a golf shaft's natural frequency in CPM (cycles per minute) in real time.

You don't attach your phone to the club. Clamp the club to the edge of a desk, lay your iPhone flat on the desk, pluck the shaft, and tap Start. The frequency appears as a large number and a graph. Because nothing is attached to the club, its mass doesn't lower the frequency, giving good absolute accuracy.

■ Features
・Real-time CPM: analyzes the shaft's vibration and shows the natural frequency in large type.
・Spectrum & peak detection: plots the vibration spectrum and automatically detects the peak (natural frequency), with an approximate ± range.
・Desk-placement method: nothing is attached to the club, so its mass doesn't lower the reading.
・Portrait & landscape layouts.
・Japanese / English, following your device language.

■ Great for
・Comparing how stiff or soft your shafts are, as numbers.
・A reference when reshafting or checking specs.
・Measuring frequency easily without dedicated equipment.

■ Please note
Readings are approximate. Please use them as a reference, not as exact frequency measurements. They are more than adequate for comparing how stiff or soft your shafts are.

This app uses only the accelerometer—no microphone, camera, or location. It collects and transmits no personal information or data.